| Abstrakt: |
The performance of gadolinium burnable absorber (GdBA) for reactivity control in UO2and (U, Th)O2fuels and its impact on spent fuel characteristics was performed. Five fuel assemblies: one without GdBA fuel rod and four each containing 16, 24, 34 and 44 GdBA fuel rods in both fuels were investigated. Reactivity swing in all the FAs with GdBA rods in UO2fuel was higher than their counterparts with similar GdBA fuel rods in (U, Th)O2fuel. The excess reactivity in all FAs with (U, Th)O2fuel was higher than UO2fuel. At the end of single discharge burn-up (~ 49.64 GWd/tHM), the excess reactivity of (U, Th)O2fuel remained positive (16,000 pcm) while UO2fuel shows a negative value (−6,000 pcm), which suggest a longer discharge burn-up in (U, Th)O2fuel. The concentration of plutonium isotopes and minor actinides were significantly higher in UO2fuel than in (U, Th)O2fuel except for 236Np. However, the concentration of non-actinides (gadolinium and iodine isotopes) except for 135Xe were respectively smaller in (U, Th)O2fuel than in UO2fuel but may be two times higher in (U, Th)O2fuel due to its potential longer discharge burn-up. |
